Clinical significance of serum ECP and sero-prevalence of human toxocariasis in patients with eosinophilia

Abstract

BACKGROUND: Several studies have reported that the serum concentration of eosinophil cationic protein (ECP) reflects the intensity of eosinophilic airway inflammation in asthmatic patients, and the ratio of serum ECP concentration to peripheral blood eosinophil counts (ECP/Eo ratio) may be useful in assessing asthma severity. Human toxocariasis, of which diagnosis relies upon specific serology, is a common. worldwide helminthozoonosis and one of the causes of blood eosinophilia. OBJECTIVES: The aim of this study is to evaluate the clinical significance of serum ECP concentration, peripheral-blood eosinophil count and ECP/Eo ratio in relation to clinical severity, and the sero-prevalence of human toxocariasis in patients with eosinophilia. MATERIALS AND METHODS: Fifteen patients with eosinophilia were enrolled. Serum ECP concentrations by CAP system, peripheral-blood eosinophil counts, and ECP/Eo ratio were determined. Clinical severity of the disease was represented as the number of organs with eosinophilic infiltration, and we divided the study subjects in to two groups according to therapeutic response. The diagnosis of toxocariasis was confirmed by detecting serum specific IgE antibody to Toxocara excretory-secretory antigens (TES-Ag) by ELISA and IgG immunoblot analysis. RESULTS: A significant positive correlation was found between the number of organs with eosinophilic infiltration, serum ECP concentration, and peak peripheral-blood eosinophil count (p < 0.05, respectively). The number of organs with eosinophilic infiltration was significantly higher in the poor therapeutic response group compared to the good therapeutic response group (p < 0.01). Fourteen of 15 patients (93.3%) showed positive reactions in Toxocara serologic test. CONCLUSION: Toxocara infection should be considered as a major cause of eosinophilia in this country. Serum ECP, peak peripheral-blood eosinophil count and the number of organs with eosinophilic infiltration may be used as useful markers for assessment of therapeutic response in patients with eosinophilia.